Histologic structure of human costochondral junction

Costochondral grafts are commonly used to restore dysplastic mandibular condyles. Despite their worldwide use, the growth of the condyle-ramus unit constructed with a costochondral graft is highly unpredictable, excess growth being the most common consequential problem. In a recent series of experiments on rats, it became evident that the amount of cartilage, more precisely the amount of germinative cells, in the rib graft has a direct bearing on its growth capacity. In the present study, the histology of the human costochondral junction of growing individuals was examined. It was implicit from the height of the proliferative plus hypertrophic cell zones of the junction that the grafts used clinically have always contained germinative cells, but in variable amounts. Thus the reported growth variability of the condyle-ramus unit may be due to the amount of cartilage included in the grafts.